Filters used by descriptors differ from filters used by operators. There are customer-level and subscription-level filters for object descriptors.
Customer-level filters can specify a customer by ID or login name. Subscription-level filters can specify a subscription by name, ID, or they can specify multiple subscriptions belonging to a specified customer by ID or login name.
If the filter node is not blank (<filter/>) the server will return descriptor for an object, specified by filtering rule parameters. In this case there will be filter-id and id nodes in the response packet.
If the filter node is blank the server will return the server-level descriptor for a specified object. In this case there will not be filter-id and id nodes in the response packet.
A single filter node cannot contain filtering parameters presented by different nodes in XML schema, but can contain multiple filtering parameters presented by the same node in XML schema.
For more information about descriptors, refer to the Descriptors Overview section.